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Subduction zone physics: Sinking of the oceanic lithosphere (sediments, crust, mantle), by the contrast of density between the cold and old lithosphere and the hot asthenospheric mantle wedge, is the strongest force (but not the only one) needed to drive plate motion and is the dominant mode of mantle convection. [citation needed]
This assemblage is associated with subduction along the trench and low heat flow. Nearest the arc is a zone of high temperature-low pressure metamorphic conditions characterized by amphibolite to granulite facies mineral assemblages such as aluminosilicates, cordierite, and orthopyroxenes. This assemblage is associated with high heat flow ...
A volcanic arc is part of an arc-trench complex, which is the part of a subduction zone that is visible at the Earth's surface. A subduction zone is where a tectonic plate composed of relatively thin, dense oceanic lithosphere sinks into the Earth's mantle beneath a less dense overriding plate. The overriding plate may be either another oceanic ...
Obduction zones occurs when the continental plate is pushed under the oceanic plate, but this is unusual as the relative densities of the tectonic plates favours subduction of the oceanic plate. This causes the oceanic plate to buckle and usually results in a new mid-ocean ridge forming and turning the obduction into subduction. [citation needed]
Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the subduction zone. They are the principal way by which continental growth is achieved. [1] The Ryukyu Islands form an island arc. Island arcs can either be active or inactive based on their seismicity and presence of ...
Here, the Pacific Plate is being subducted underneath the North American Plate and the rate of subduction changes from west to east from 7.5 to 5.1 cm (3.0 to 2.0 in) per year. [2] The Aleutian subduction zone includes two prominent features, the Aleutian Arc and the Aleutian Trench. The Aleutian Arc was created via volcanic eruptions from ...
The subduction zone was curved in an arc, resulting in compression in the west-southwest east-northeast direction as well as sinistral shear in the New England district. A continental fragment may have collided with the area, pushing off the Hastings Block and fracturing the Barnard Basin.
The subduction of bathymetric highs such as aseismic ridges, oceanic plateaus, and seamounts has been posited as the primary driver of flat slab subduction. [3] The Andean flat slab subduction zones, the Peruvian slab and the Pampean (Chilean) flat slab, are spatially correlated with the subduction of bathymetric highs, the Nazca Ridge and the Juan Fernandéz Ridge, respectively.